PROJECT SUMMARY/ABSTRACT Thoracic epidural analgesia (TEA) is the gold standard for treating acute pain following major thoracic and abdominal surgeries and in patients with fractured ribs. Of the 51 million inpatient surgeries performed in the US each year, an estimated 3 - 6 million are eligible for TEA. Multiple randomized control trials have demonstrated significantly improved patient outcomes when receiving TEA instead of systemic opioids, including reduced 90-day mortality (3.1 vs 4.9%), improved postoperative pain control, reduced pulmonary and cardiovascular complications, and reduced incidence of chronic pain syndromes. In addition, TEA is associated with increased patient satisfaction, shortened hospital stays, and a significant reduction in the cost of perioperative care (e.g. savings between $4,675 - $22,000 per patient vs systemic opioids). However, TEA is regarded as one of the most technically difficult procedures executed by anesthesiologists, in large part because epidural needle placement is guided by manual palpation of spinal bone landmarks followed by ?blind? needle insertion. Palpation of spine landmarks is unreliable for identifying the epidural space (i.e. 30% accuracy) and results in high TEA failure rates (15 ? 35%) due to catheter misplacement outside of the intended epidural space. Halving the number of TEA failures per year is estimated to reduce the number of postoperative deaths by 25,000 per year and result in a $15.5B/yr economic benefit due to reduced cost of care and fewer premature deaths. During the Phase I project, the feasibility of a low-cost, handheld ultrasound system and new automated image guidance technologies was demonstrated by imaging in vitro thoracic spine phantoms and human thoracic spines. This Phase II proposal seeks funding to support the continued development of a low-cost, handheld medical device for thoracic epidural guidance. The key technological innovations of this project are focused on improvements to ultrasound-based beamforming for enhanced bone visualization and include a new spinal bone imaging approach that enables the automatic detection of spinal bone landmarks and needle insertion site. The long-term goal of this project is to demonstrate a portable, low-cost, ultrasound-based medical device that facilitates thoracic epidural placement in the postoperative patient population, improves success rates, and lowers the risk of associated health complications. The Phase II hypothesis is that the handheld medical imaging device and associated technologies increases first-attempt epidural analgesia success rates, defined as successful epidural administration on the first needle insertion attempt. New ultrasound beamforming technologies for a low-channel count ultrasound transducer design for improved bone imaging performance will be designed, fabricated, and tested. In addition, ultrasound imaging technologies central to this project will be optimized, integrated into the new device, and validated in a clinical study. Finally, the Phase II hypothesis will be directly tested in an 80 patient clinical study. With an estimated 3 ? 6 million patients eligible for thoracic epidural administration each year, the estimated US market size for the proposed device is $325 M/yr.